How Sugar Substitutes Stack Up

We put them to the test by baking cakes.

There are plenty of reasons to avoid fructose (a.k.a. sugar, the subject of the cover story in this month's issue of National Geographic magazine) and its even more vilified twin, high-fructose corn syrup.

For athletes, these sweeteners provide much-needed energy. For the rest of us, they're high-calorie, zero-nutrition temptations that can lead to obesity and a host of related conditions—diabetes, high cholesterol, heart disease.

When sugar has a rap sheet like this, alternative sweeteners start to look appealing. For diabetics, most of these substitutes don't cause the dramatic blood sugar spikes associated with the real thing. For weight watchers, zero (or dramatically reduced) calories are a dieter's boon.

But which to choose? There are scores of sugar substitutes; most fall into one of four categories: natural sweeteners, artificial sweeteners, dietary supplements, and sugar alcohols. And there's a new hybrid sweetener—tagatose—that is natural and has fewer calories than sugar.

Natural Sweeteners

As a category, natural sweeteners are a less processed, better-for-you-option than fructose. Like sugar, they produce energy when metabolized by the body. Unlike sugar, they have some nutritional value in the form of trace vitamins and minerals.

There's agave from the eponymous plant, honey (actually sweeter than sugar, so you don't need as much), molasses, and the syrup family (barley, malt, brown rice, cane, corn, golden, maple). Over the years I've performed enough tests to know that while there are taste and textural differences, most of these more distinctive sweeteners are fine stand-ins for sugar.

Dieters take note: This category of sweeteners is not low-cal. For diabetics, however, many of these sweeteners have a low glycemic index, which means they don't cause the highs and lows that come with sugar and high-fructose corn syrup.

Artificial Sweeteners

Artificial sweeteners (or zero-calorie sweeteners) include the big three: Sweet'N Low, Nutrasweet, and Splenda. These synthetically produced food additives offer sweetness without calories—but having no calories means they give your body no energy. These sweeteners pass through the body undigested. And they're so intensely sweet that they must be diluted with fillers like dextrose or maltodextrin to approximate the sweetness—and bulk—of sugar.

Almost all artificial sweeteners have a distinct aftertaste, but regular users find them to be good sugar substitutes in drinks and tend to be passionate about their favorite.

As a category, artificial sweeteners did not impress in the oven. They may mimic the taste of sugar in a latte, but they don't perform like sugar in a cake. There are two issues. Artificial sweeteners lack sugar's bulk. Compared with sugar-sweetened cakes, artificially sweetened ones are dense and squat. You could solve the volume problem by increasing the batter, but that means more flour and butter (carbs and calories). Artificial sweeteners don't melt like sugar, so the cake's texture is often dense, dry, and lumpy—more like a biscuit than a cake.

Here's how the artificial sweeteners stack up in baking.

Acesulfame potassium (or acesulfame K or ace-K) is about 200 times sweeter than sugar and has no calories.

Brand names: Sunett, Sweet One (very limited retail distribution, available only in small packets)

Used for baking: Yes, at temperatures below 400°F. (Because Sweet One is not available in my area and comes only in small retail packets, I did not test this brand.)

Aspartame is also about 200 times sweeter than sugar and is completely broken down by the body into its two component amino acids—aspartic acid and phenylalanine (and a small amount of methanol or wood alcohol). It actually contains 4 calories per gram, but since so little is used there are only trace calories per serving.

Aspartame is not safe for those with the rare but serious metabolic disorder phenylketonuria (PKU). Those with PKU cannot process the amino acid phenylalanine, and too much of it in the body's system can lead to mental retardation, low IQ, and behavioral problems.

Used for baking: Some sources said yes; others said heat caused it to lose its sweetness. The latter, in fact, is true. The cake I baked was not sweet.

Neotame is made by Nutrasweet. The newest of the artificial sweeteners, it is about 40 times sweeter than aspartame (making it 8,000 times sweeter than sugar) and is metabolized like aspartame.

Brand name: Neotame (not available to consumers)

Used for baking: It is said to be much more stable than aspartame for baking and cooking. (Since it is not available in retail outlets, I did not test it.)

Saccharin (or benzoic sulfimide), the oldest of the artificial sweeteners, was accidentally discovered by a chemist working on coal tar derivatives more than 100 years ago. Depending on its use, it can be 200 to 700 times sweeter than sugar.

Brand names: Sweet'N Low, Sweet Twin, and Necta Sweet

Used for baking: Yes. Although the cake I baked was dense and lumpy, it was surprisingly tender and very sweet, with that unmistakable metallic Sweet'N Low aftertaste.

Sucralose (or chlorinated sugar) was accidentally discovered in 1976 by a researcher and was approved for use in the U.S. in 1998. It is 600 times sweeter than regular sugar and is marketed as a sugar substitute that can fill in for the real thing in any capacity, including cake baking.

Brand name: Splenda

Used for baking: Splenda is popular because it can retain its natural sweetness when heated to high temperatures. The cake I baked had a biscuit-like texture, consistent with that of cakes baked with the other artificial sweeteners. The aftertaste is not as strong as Sweet'N Low's but is noticeable.

Dietary Supplements

Stevia is a virtually calorie-free sweetener that is 200 times sweeter than sugar; it has been used for centuries as a sweetener in South America. In the 1980s, tests on stevia had problematic results: Animal studies linked stevia to a negative impact on fertility and possible genetic mutations. As a result, pure stevia is categorized as a dietary supplement not approved by the U.S. Food and Drug Administration. In 2008, however, the makers of Truvia and PureVia petitioned the FDA, which ultimately granted GRAS (generally recognized as safe) status to the highly purified extract of stevia called rebaudioside A (also known reb A or Rebiana).

Even though it is derived from a plant, some consider it artificial because it is so highly refined. For now, FDA-approved stevia products like Truvia and PureVia are widely available. For pure stevia, head to a health-food store or vitamin shop.

Used for baking: Yes, but like many of the artificial sweeteners, pure stevia doesn't have the bulk to deliver appealing baked goods. The cake made with Truvia was acceptable, but there was a mild vanilla aftertaste that is apparently added to disguise the more obvious licorice finish.

Lo Han Kuo (or monk fruit) is an ancient Chinese fruit about 200 times sweeter than sugar; it received FDA GRAS status in 2009. Stirred into a drink, the Nectresse brand blend most closely approximates sugar and was one of my favorite no-calorie sweeteners.

Used for baking: Yes. Nectresse performed similarly to the other no-cal sweeteners, producing a cake that was tender but lumpy, dry, and biscuit-like.

Sugar Alcohols

Not all non-nutritive sweeteners are artificial. Sugar alcohols, or sugar/alcohol hybrids, are natural, not chemically derived. Since they are not completely absorbed by the body, these plant-based sweeteners have fewer calories than sugar does. The body absorbs sugar alcohols more slowly than it absorbs sugars, so these products are lower on the glycemic index.

It's easy to identify sugar alcohols on packaging labels because most of them end in "ol"—glucitol, sorbitol, maltitol, mannitol, glycerol, lactitol. Many of them have a cool, fresh finish associated with mints, gum, and cough syrups, so it's no surprise that these are the sugars used to sweeten those products.

Products containing sugar alcohols can be labeled "sugar free" or "reduced calorie," so be aware that sugar free does not necessarily mean calorie free. Consuming excessive amounts of sugar alcohol can cause gas and/or diarrhea, which I have confirmed with regular users.

The two most common sugar alcohols available to consumers are no-calorie erythritol and reduced-calorie xylitol, both of which baked up into very respectable cakes. Although there was some criticism that sugar alcohols don't brown when heated, I didn't find it to be true. Perhaps it was from the butter and milk, but both the erythritol and the xylitol cakes were golden brown.

Erythritol has the calorie advantage over xylitol—zero calories compared with xylitol's nine calories per teaspoon. Of all the zero-calorie sweeteners, erythritol was my overall favorite in its baking performance and clean flavor.

Brand names: ZSweet, Sweet Simplicity, Zero

Used for baking: Yes—the erythritol-sweetened cake was a runner-up in my personal baking contest. Though not as good as the xylitol-sweetened cake, it was far superior in taste and texture to the cakes made with other zero-calorie sweeteners.

Xylitol is five percent less sweet than sugar, but it has 40 percent fewer calories (9 calories versus sugar's 16) and a low glycemic index. It can be made from many different things, but it's primarily extracted from corncobs and hardwoods. It is increasingly difficult to find the better-for-you xylitol made from hardwoods. The bulk of xylitol is made from corn and imported from China.

Brand names: XyloSweet, XyloPure, Miracle Sweet, Nature's Provision

Used in baking: Yes. Xylitol looks like sugar, tastes like sugar, and responds like sugar in baking. Among the sugar substitutes, xylitol is my favorite. Though it was not as sweet as the cake sweetened with sugar, the xylitol cake's texture was tender and cake-like and the flavor was pure.

The New Hybrid

Tagatose is a new naturally occurring sweetener found in milk. It's 92 percent as sweet with only a third of the calories of sugar. Like yogurt, it contains probiotics, which means it helps the good bacteria in the digestive system multiply. It has a clean neutral taste, and it browns very well in baked goods.

Brand name: PreSweet

Used in baking: Yes. Although the tagatose-sweetened cake was very tender, the crumb was gummy with a slightly sour finish. A xylitol-tagatose blend could be a winning combination.

Conclusion: Weighing Risks and Benefits

Although no hard link between artificial sweeteners and cancer has been established, suspicions linger from the famous 1970s experiment showing that lab animals given extremely high doses of a cyclamate-saccharine combination were prone to bladder cancer. Subsequent studies seemed to limit the artificial sweetener/cancer connection to lab animals only, and to date no direct correlation between artificial sweeteners and cancer in humans has been shown.

An interesting link, however, has been reported between artificial sweeteners and weight gain. Despite the apparent logic, research and repeated studies point to artificial and no- and low-calorie sweeteners actually causing weight gain. It appears that once we get a hit of sweet taste without the calories, it increases our food cravings, and we eat more.

For diabetics, sugar substitutes are a necessary and pleasurable alternative. For those trying to shave a few calories out of their daily diet, the occasional diet soft drink or artificially sweetened cup of coffee is fine, and lower-calorie xylitol is a great option for baking.

As for those who habitually use artificial sweeteners to lose weight—yet without success—the path to actual weight loss may be the counterintuitive one: making peace with sugar.

Pam Anderson is a New York Times best-selling author. Her most recent book is Cook Without a Book: Meatless Meals. She's working on a new volume with her two daughters. The three of them blog at threemanycooks.com.